Gmat Prep exam question

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Gmat Prep exam question

by Fab_Vr6 » Sun Jun 17, 2007 12:30 pm
If X<0, then Sq root (-X lXl ) = ?

a) -X
b) -1
c) 1
d) x
E) Sq root X

why is the answer a) not d)? I thought lxl = +X , and - (-x) = +x , so the product of these are X^2. Sq root of this is X. no?
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Re: Gmat Prep exam question

by jayhawk2001 » Sun Jun 17, 2007 1:56 pm
Fab_Vr6 wrote:If X<0, then Sq root (-X lXl ) = ?

a) -X
b) -1
c) 1
d) x
E) Sq root X

why is the answer a) not d)? I thought lxl = +X , and - (-x) = +x , so the product of these are X^2. Sq root of this is X. no?
sqrt (number) is always positive. Since x is negative, we cannot have +x
as the answer. Only -x (positive number when x is negative) will satisfy
the condition

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by ashok_uddaraju » Wed Jun 20, 2007 12:27 am
i guess some imaginary no "i" should have accompanied the answer choices